ipcLockService.cpp

/* vim:set ts=4 sw=4 sts=4 et cindent: *//* ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is Mozilla IPC. * * The Initial Developer of the Original Code is * Netscape Communications Corporation. * Portions created by the Initial Developer are Copyright (C) 2002 * the Initial Developer. All Rights Reserved. * * Contributor(s): * Darin Fisher <darin@netscape.com> * * Alternatively, the contents of this file may be used under the terms of * either the GNU General Public License Version 2 or later (the "GPL"), or * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */#include <stdlib.h>#include "nsDependentString.h"#include "nsHashKeys.h"#include "nsAutoPtr.h"#include "ipcLockService.h"#include "ipcLockProtocol.h"#include "ipcLog.h"#include "prthread.h"staticconstnsID kLockTargetID = IPC_LOCK_TARGETID;
//-----------------------------------------------------------------------------struct ipcPendingLock
{
constchar *name;
nsresult status;
PRBool complete;
};
//-----------------------------------------------------------------------------
nsresult
ipcLockService::Init()
{
if (PR_NewThreadPrivateIndex(&mTPIndex, nsnull) != PR_SUCCESS)
return NS_ERROR_OUT_OF_MEMORY;
// Configure OnMessageAvailable to be called on the IPC thread. This is// done to allow us to proxy OnAcquireLockComplete events to the right// thread immediately even if the main thread is blocked waiting to acquire// some other lock synchronously.return IPC_DefineTarget(kLockTargetID, this, PR_FALSE);
}
NS_IMPL_THREADSAFE_ISUPPORTS2(ipcLockService, ipcILockService, ipcIMessageObserver)
NS_IMETHODIMP
ipcLockService::AcquireLock(const char *lockName, PRBool waitIfBusy)
{
LOG(("ipcLockService::AcquireLock [lock=%s wait=%u]\n", lockName, waitIfBusy));
ipcLockMsg msg;
msg.opcode = IPC_LOCK_OP_ACQUIRE;
msg.flags = (waitIfBusy ? 0 : IPC_LOCK_FL_NONBLOCKING);
msg.key = lockName;
PRUint32 bufLen;
nsAutoPtr<PRUint8> buf( IPC_FlattenLockMsg(&msg, &bufLen) );
if (!buf)
return NS_ERROR_OUT_OF_MEMORY;
ipcPendingLock pendingLock;
pendingLock.name = lockName;
pendingLock.status = 0xDEADBEEF; // something bogus
pendingLock.complete = PR_FALSE;
if (PR_SetThreadPrivate(mTPIndex, &pendingLock) != PR_SUCCESS)
return NS_ERROR_UNEXPECTED;
// prevent our OnMessageAvailable from being called until we explicitly ask// for it to be called via IPC_WaitMessage.
IPC_DISABLE_MESSAGE_OBSERVER_FOR_SCOPE(kLockTargetID);
nsresult rv = IPC_SendMessage(0, kLockTargetID, buf, bufLen);
if (NS_SUCCEEDED(rv)) {
do {
// block the calling thread until we get a response from the daemon
rv = IPC_WaitMessage(0, kLockTargetID, this, nsnull, PR_INTERVAL_NO_TIMEOUT);
}
while (NS_SUCCEEDED(rv) && !pendingLock.complete);
if (NS_SUCCEEDED(rv))
rv = pendingLock.status;
}
// we could clear the TPD, but that isn't really necessary.return rv;
}
NS_IMETHODIMP
ipcLockService::ReleaseLock(constchar *lockName)
{
LOG(("ipcLockService::ReleaseLock [lock=%s]\n", lockName));
ipcLockMsg msg;
msg.opcode = IPC_LOCK_OP_RELEASE;
msg.flags = 0;
msg.key = lockName;
PRUint32 bufLen;
PRUint8 *buf = IPC_FlattenLockMsg(&msg, &bufLen);
if (!buf)
return NS_ERROR_OUT_OF_MEMORY;
nsresult rv = IPC_SendMessage(0, kLockTargetID, buf, bufLen);
delete buf;
if (NS_FAILED(rv))
return rv;
return NS_OK;
}
// called on the same thread that called IPC_WaitMessage
NS_IMETHODIMP
ipcLockService::OnMessageAvailable(PRUint32 unused, constnsID &target,
const PRUint8 *data, PRUint32 dataLen)
{
ipcLockMsg msg;
IPC_UnflattenLockMsg(data, dataLen, &msg);
LOG(("ipcLockService::OnMessageAvailable [lock=%s opcode=%u]\n", msg.key, msg.opcode));
ipcPendingLock *pendingLock = (ipcPendingLock *) PR_GetThreadPrivate(mTPIndex);
if (strcmp(pendingLock->name, msg.key) == 0) {
pendingLock->complete = PR_TRUE;
if (msg.opcode == IPC_LOCK_OP_STATUS_ACQUIRED)
pendingLock->status = NS_OK;
else
pendingLock->status = NS_ERROR_FAILURE;
return NS_OK;
}
LOG(("message does not match; waiting for another...\n"));
// else, we got a message that another thread is waiting to receive.return IPC_WAIT_NEXT_MESSAGE;
}